Roger Mason Jr. did not go quietly into the night after being fired as commissioner of the Big3 basketball league for alleged corruption. The former NBA player and high-ranking official with that league’s union claimed Monday that a “hostile and racist” environment existed at the three-on-three basketball league, which debuted last year as the brainchild of actor/rapper Ice Cube.

In a statement provided to The Washington Post, Mason said that he was fired in retaliation for accusing the Big3, and in particular co-founder Jeff Kwatinetz, of breaching his employment agreement. Mason added that “a former employee of BIG3″ recently told him that Kwatinetz, an entertainment industry executive, “has repeatedly referred to black athletes as ‘rich (expletive).’ ”

According to TMZ Sports, which said it obtained a letter sent to players and league employees, Mason was fired for corrupt practices, following an investigation into his ties to a pair of Qatari investors in the league, Ayman Sabi and Ahmed Al-Rumaihi, who were alleged to have withheld millions of dollars from the Big3. When the Big3 sued the two men, Mason allegedly refused to work on the league’s behalf in the matter.

The Qataris were said to have bestowed gifts and other benefits on a few Big3 officials, per the website, with the implication that Mason’s integrity had been compromised. Ice Cube is reportedly set to step in as the league’s commissioner until a permanent replacement is found.

“I am disappointed at the conduct of Ice Cube and other executives of Big3 in leveling these desperate manufactured claims against me,” Mason said. He added that Kwatinetz “has been engaged in a malicious, defamatory campaign of disparaging me in an attempt to prevent me from the performance of contractual duties and responsibilities.”

A spokesman for the Big3 told The Post that the league would not have “any comment at this time.”

A Washington, D.C.-area native who starred at Good Counsel High and the University of Virginia, Mason played for 10 years in the NBA, including three with the Wizards. The 37-year-old former shooting guard had been deputy executive director of the NBA Players Association, where he helped negotiate that league’s collective bargaining agreement, before joining the Big3 as its commissioner.

“As a fan, I’m just excited to see the guys that I know play at a competitive, high level,” Ice Cube said at a January 2017 news conference unveiling the league. “I’m just happy I have the right people and partners to be able to provide the stage for them.”

“Although it’s been a lot of fun, there hasn’t been a lot of sleep,” Mason said last year of his experience as commissioner (via uvamagazine.org). “Starting from scratch and really building out with a small infrastructure, it’s been anything you can imagine. We’ve been all hands on deck – whether that was putting together presentations for the sponsors or reaching out to the players to give them a vision of what this league would look like.”

The news about Mason overshadowed the Big3’s announcement Monday of the schedule for its second season, which will feature some notable new names. Former NBA stars such as Amar’e Stoudemire, Metta World Peace and Baron Davis are joining the league, which starts a 10-week season in June and is set to play its games in Houston, Chicago, Oakland, Detroit, Miami, Toronto, Boston, Atlanta, Dallas and New York.